1. Technical Field
The present invention generally relates to an optical component; and more particularly to an optical component having a Bragg grating written therein.
2. Description of Related Art
U.S. Pat. No. 5,337,382 discloses a 125 micron optical fiber having a Bragg grating written therein at an oblique angle, which are known in the art as blazed gratings. The subject matter of U.S. Pat. No. 5,337,382 is hereby incorporated by reference herein. One disadvantage of this optical fiber design is that it is not readily adaptable to compression-based designs for tuning the Bragg grating, because the 125 micron optical fiber tends to buckle under a compressive force. Thus, it is advantageous and desirable to provide an optical component that is readily adaptable to compression-based designs for tuning the Bragg grating without bending.
In its broadest sense, the present invention provides a large diameter optical waveguide having a diameter of at least about 0.3 millimeters, and an outer cladding surrounding an inner core with a blazed grating therein. The blazed grating is written into the inner core at an oblique angle relative to a longitudinal axis of the inner core for attenuating optical light traveling in the optical waveguide, or for reflecting and coupling optical light to or from the optical waveguide and a light source or receiver.
The blazed grating has an optical parameter that changes in response to an application of a compressive force on the optical waveguide. The blazed grating may include a plurality of concatenated periodic or aperiodic gratings. The outer cladding may also have the blazed grating written therein, or a combination of the inner core and the cladding may have the blazed grating therein. The optical waveguide may be shaped like a dogbone structure having wider outer sections and a narrower central section inbetween. The blazed grating is written in the narrower central section of the dogbone structure. The narrower central section may have a tapered shape, including linear, quadratic or step-like tapering. The narrower intermediate section may also have a thermal device wrapped around, or otherwise positioned in heat exchange relationship with, the narrower central section of the optical waveguide to tune the center wavelength of the blazed grating along a spectral range.
The large diameter waveguide having the blazed grating therein and the compression-based tuning approach for tuning the same will open up a whole new host of optical coupling applications, optical attenuating applications, as well as parameter sensing applications and optical signal filtering applications not otherwise possible when using the prior art 125 micron tension-based tuned optical fiber.
The foregoing and other objects, features and advantages of the present invention will become more apparent in light of the following detailed description of exemplary embodiments thereof.